Matching Items (326)
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Background: Hemorrhagic fever with renal syndrome (HFRS), a rodent-borne infectious disease, is one of the most serious public health threats in China. Increasing our understanding of the spatial and temporal patterns of HFRS infections could guide local prevention and control strategies.

Methodology/Principal Findings: We employed statistical models to analyze HFRS case data together

Background: Hemorrhagic fever with renal syndrome (HFRS), a rodent-borne infectious disease, is one of the most serious public health threats in China. Increasing our understanding of the spatial and temporal patterns of HFRS infections could guide local prevention and control strategies.

Methodology/Principal Findings: We employed statistical models to analyze HFRS case data together with environmental data from the Dongting Lake district during 2005–2010. Specifically, time-specific ecologic niche models (ENMs) were used to quantify and identify risk factors associated with HFRS transmission as well as forecast seasonal variation in risk across geographic areas. Results showed that the Maximum Entropy model provided the best predictive ability (AUC = 0.755). Time-specific Maximum Entropy models showed that the potential risk areas of HFRS significantly varied across seasons. High-risk areas were mainly found in the southeastern and southwestern areas of the Dongting Lake district. Our findings based on models focused on the spring and winter seasons showed particularly good performance. The potential risk areas were smaller in March, May and August compared with those identified for June, July and October to December. Both normalized difference vegetation index (NDVI) and land use types were found to be the dominant risk factors.

Conclusions/Significance: Our findings indicate that time-specific ENMs provide a useful tool to forecast the spatial and temporal risk of HFRS.

ContributorsLiu, Hai-Ning (Author) / Gao, Li-Dong (Author) / Chowell-Puente, Gerardo (Author) / Hu, Shi-Xiong (Author) / Lin, Xiao-Ling (Author) / Li, Xiu-Jun (Author) / Ma, Gui-Hua (Author) / Huang, Ru (Author) / Yang, Hui-Suo (Author) / Tian, Huaiyu (Author) / Xiao, Hong (Author) / Simon M. Levin Mathematical, Computational and Modeling Sciences Center (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2014-09-03
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We conducted a 12-month-long experiment in a financial services company to study how the availability of treadmill workstations affects employees’ physical activity and work performance. We enlisted sedentary volunteers, half of whom received treadmill workstations during the first two months of the study and the rest in the seventh month

We conducted a 12-month-long experiment in a financial services company to study how the availability of treadmill workstations affects employees’ physical activity and work performance. We enlisted sedentary volunteers, half of whom received treadmill workstations during the first two months of the study and the rest in the seventh month of the study. Participants could operate the treadmills at speeds of 0–2 mph and could use a standard chair-desk arrangement at will. (a) Weekly online performance surveys were administered to participants and their supervisors, as well as to all other sedentary employees and their supervisors. Using within-person statistical analyses, we find that overall work performance, quality and quantity of performance, and interactions with coworkers improved as a result of adoption of treadmill workstations. (b) Participants were outfitted with accelerometers at the start of the study. We find that daily total physical activity increased as a result of the adoption of treadmill workstations.

ContributorsBen-Ner, Avner (Author) / Hamann, Darla J. (Author) / Koepp, Gabriel (Author) / Manohar, Chimnay U. (Author) / Levine, James (Author) / School of Human Evolution and Social Change (Contributor)
Created2014-02-20
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Description

Background:
Pandemic influenza is said to 'shift mortality' to younger age groups; but also to spare a subpopulation of the elderly population. Does one of these effects dominate? Might this have important ramifications?

Methods: We estimated age-specific excess mortality rates for all-years for which data were available in the 20th century for Australia,

Background:
Pandemic influenza is said to 'shift mortality' to younger age groups; but also to spare a subpopulation of the elderly population. Does one of these effects dominate? Might this have important ramifications?

Methods: We estimated age-specific excess mortality rates for all-years for which data were available in the 20th century for Australia, Canada, France, Japan, the UK, and the USA for people older than 44 years of age. We modeled variation with age, and standardized estimates to allow direct comparison across age groups and countries. Attack rate data for four pandemics were assembled.

Results: For nearly all seasons, an exponential model characterized mortality data extremely well. For seasons of emergence and a variable number of seasons following, however, a subpopulation above a threshold age invariably enjoyed reduced mortality. 'Immune escape', a stepwise increase in mortality among the oldest elderly, was observed a number of seasons after both the A(H2N2) and A(H3N2) pandemics. The number of seasons from emergence to escape varied by country. For the latter pandemic, mortality rates in four countries increased for younger age groups but only in the season following that of emergence. Adaptation to both emergent viruses was apparent as a progressive decrease in mortality rates, which, with two exceptions, was seen only in younger age groups. Pandemic attack rate variation with age was estimated to be similar across four pandemics with very different mortality impact.

Conclusions: In all influenza pandemics of the 20th century, emergent viruses resembled those that had circulated previously within the lifespan of then-living people. Such individuals were relatively immune to the emergent strain, but this immunity waned with mutation of the emergent virus. An immune subpopulation complicates and may invalidate vaccine trials. Pandemic influenza does not 'shift' mortality to younger age groups; rather, the mortality level is reset by the virulence of the emerging virus and is moderated by immunity of past experience. In this study, we found that after immune escape, older age groups showed no further mortality reduction, despite their being the principal target of conventional influenza vaccines. Vaccines incorporating variants of pandemic viruses seem to provide little benefit to those previously immune. If attack rates truly are similar across pandemics, it must be the case that immunity to the pandemic virus does not prevent infection, but only mitigates the consequences.

Created2012-12-12
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In this paper, we present a visual analytics approach that provides decision makers with a proactive and predictive environment in order to assist them in making effective resource allocation and deployment decisions. The challenges involved with such predictive analytics processes include end-users' understanding, and the application of the underlying statistical

In this paper, we present a visual analytics approach that provides decision makers with a proactive and predictive environment in order to assist them in making effective resource allocation and deployment decisions. The challenges involved with such predictive analytics processes include end-users' understanding, and the application of the underlying statistical algorithms at the right spatiotemporal granularity levels so that good prediction estimates can be established. In our approach, we provide analysts with a suite of natural scale templates and methods that enable them to focus and drill down to appropriate geospatial and temporal resolution levels. Our forecasting technique is based on the Seasonal Trend decomposition based on Loess (STL) method, which we apply in a spatiotemporal visual analytics context to provide analysts with predicted levels of future activity. We also present a novel kernel density estimation technique we have developed, in which the prediction process is influenced by the spatial correlation of recent incidents at nearby locations. We demonstrate our techniques by applying our methodology to Criminal, Traffic and Civil (CTC) incident datasets.

Created2014-12-01
Description

Rho GTPases are frequent targets of virulence factors as they are keystone signaling molecules. Herein, we demonstrate that AMPylation of Rho GTPases by VopS is a multifaceted virulence mechanism that counters several host immunity strategies. Activation of NFκB, Erk, and JNK kinase signaling pathways were inhibited in a VopS-dependent manner

Rho GTPases are frequent targets of virulence factors as they are keystone signaling molecules. Herein, we demonstrate that AMPylation of Rho GTPases by VopS is a multifaceted virulence mechanism that counters several host immunity strategies. Activation of NFκB, Erk, and JNK kinase signaling pathways were inhibited in a VopS-dependent manner during infection with Vibrio parahaemolyticus. Phosphorylation and degradation of IKBα were inhibited in the presence of VopS as was nuclear translocation of the NFκB subunit p65. AMPylation also prevented the generation of superoxide by the phagocytic NADPH oxidase complex, potentially by inhibiting the interaction of Rac and p67. Furthermore, the interaction of GTPases with the E3 ubiquitin ligases cIAP1 and XIAP was hindered, leading to decreased degradation of Rac and RhoA during infection. Finally, we screened for novel Rac1 interactions using a nucleic acid programmable protein array and discovered that Rac1 binds to the protein C1QA, a protein known to promote immune signaling in the cytosol. Interestingly, this interaction was disrupted by AMPylation. We conclude that AMPylation of Rho Family GTPases by VopS results in diverse inhibitory consequences during infection beyond the most obvious phenotype, the collapse of the actin cytoskeleton.

ContributorsWoolery, Andrew R. (Author) / Yu, Xiaobo (Author) / LaBaer, Joshua (Author) / Orth, Kim (Author) / Biodesign Institute (Contributor)
Created2014-11-21
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Methicillin resistant Staphylococcus aureus (MRSA) is currently a major cause of skin and soft tissue infections (SSTI) in the United States. Seasonal variation of MRSA infections in hospital settings has been widely observed. However, systematic time-series analysis of incidence data is desirable to understand the seasonality of community acquired (CA)-MRSA

Methicillin resistant Staphylococcus aureus (MRSA) is currently a major cause of skin and soft tissue infections (SSTI) in the United States. Seasonal variation of MRSA infections in hospital settings has been widely observed. However, systematic time-series analysis of incidence data is desirable to understand the seasonality of community acquired (CA)-MRSA infections at the population level. In this paper, using data on monthly SSTI incidence in children aged 0–19 years and enrolled in Medicaid in Maricopa County, Arizona, from January 2005 to December 2008, we carried out time-series and nonlinear regression analysis to determine the periodicity, trend, and peak timing in SSTI incidence in children at different age: 0-4 years, 5-9 years, 10-14 years, and 15-19 years. We also assessed the temporal correlation between SSTI incidence and meteorological variables including average temperature and humidity. Our analysis revealed a strong annual seasonal pattern of SSTI incidence with peak occurring in early September. This pattern was consistent across age groups. Moreover, SSTIs followed a significantly increasing trend over the 4-year study period with annual incidence increasing from 3.36% to 5.55% in our pediatric population of approximately 290,000. We also found a significant correlation between the temporal variation in SSTI incidence and mean temperature and specific humidity. Our findings could have potential implications on prevention and control efforts against CA-MRSA.

Created2013-04-02
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The large-scale use of antivirals during influenza pandemics poses a significant selection pressure for drug-resistant pathogens to emerge and spread in a population. This requires treatment strategies to minimize total infections as well as the emergence of resistance. Here we propose a mathematical model in which individuals infected with wild-type

The large-scale use of antivirals during influenza pandemics poses a significant selection pressure for drug-resistant pathogens to emerge and spread in a population. This requires treatment strategies to minimize total infections as well as the emergence of resistance. Here we propose a mathematical model in which individuals infected with wild-type influenza, if treated, can develop de novo resistance and further spread the resistant pathogen. Our main purpose is to explore the impact of two important factors influencing treatment effectiveness: i) the relative transmissibility of the drug-resistant strain to wild-type, and ii) the frequency of de novo resistance. For the endemic scenario, we find a condition between these two parameters that indicates whether treatment regimes will be most beneficial at intermediate or more extreme values (e.g., the fraction of infected that are treated). Moreover, we present analytical expressions for effective treatment regimes and provide evidence of its applicability across a range of modeling scenarios: endemic behavior with deterministic homogeneous mixing, and single-epidemic behavior with deterministic homogeneous mixing and stochastic heterogeneous mixing. Therefore, our results provide insights for the control of drug-resistance in influenza across time scales.

Created2013-03-29
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The Middle Stone Age (MSA) is associated with early evidence for symbolic material culture and complex technological innovations. However, one of the most visible aspects of MSA technologies are unretouched triangular stone points that appear in the archaeological record as early as 500,000 years ago in Africa and persist throughout

The Middle Stone Age (MSA) is associated with early evidence for symbolic material culture and complex technological innovations. However, one of the most visible aspects of MSA technologies are unretouched triangular stone points that appear in the archaeological record as early as 500,000 years ago in Africa and persist throughout the MSA. How these tools were being used and discarded across a changing Pleistocene landscape can provide insight into how MSA populations prioritized technological and foraging decisions. Creating inferential links between experimental and archaeological tool use helps to establish prehistoric tool function, but is complicated by the overlaying of post-depositional damage onto behaviorally worn tools. Taphonomic damage patterning can provide insight into site formation history, but may preclude behavioral interpretations of tool function. Here, multiple experimental processes that form edge damage on unretouched lithic points from taphonomic and behavioral processes are presented. These provide experimental distributions of wear on tool edges from known processes that are then quantitatively compared to the archaeological patterning of stone point edge damage from three MSA lithic assemblages—Kathu Pan 1, Pinnacle Point Cave 13B, and Die Kelders Cave 1. By using a model-fitting approach, the results presented here provide evidence for variable MSA behavioral strategies of stone point utilization on the landscape consistent with armature tips at KP1, and cutting tools at PP13B and DK1, as well as damage contributions from post-depositional sources across assemblages. This study provides a method with which landscape-scale questions of early modern human tool-use and site-use can be addressed.

ContributorsSchoville, Benjamin J. (Author) / Brown, Kyle S. (Author) / Harris, Jacob (Author) / Wilkins, Jayne (Author) / School of Human Evolution and Social Change (Contributor)
Created2016-10-13
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Education plays a key role throughout many different fields of study. My question has to do with not what we are learning, but how we are learning it, therefore focusing more on the teaching and instructional design aspect of the learning process. Specifically, the goal of my thesis is to

Education plays a key role throughout many different fields of study. My question has to do with not what we are learning, but how we are learning it, therefore focusing more on the teaching and instructional design aspect of the learning process. Specifically, the goal of my thesis is to theoretically define collaborative learning and develop a framework that demonstrates how collaboration and interactivity can be successfully implemented in a language learning classroom. Language learning is essential in schools because it enables students to be culturally aware. According to the Modern Language Teachers' Association of South Australia, language learning plays a significant role in 21st Century learning. It assists students in being more community engaged as well as culturally diverse. They state that "knowing additional languages and cultures involves connecting, engaging, and interacting with others and negotiating boundaries based on diverse ways of understanding the world." (MLTASA) Collaboration can be very beneficial in the human learning process. According to Webb, students that collaborate with each other engage in challenging conversations and produce joint solutions whereas students that don't collaborate engage in conversation about practical rather than abstract matters (Webb, 2009). The success of collaboration is defined by the content of the dialog, groups won't necessarily engage in beneficial dialogue without help and facilitation by the teacher. It's important for teachers to keep groups on task and monitor their progress throughout the lesson. Through collaborative learning the student is able to take more from the lesson and view each concept from an alternate perspective. With teacher facilitated group discussions, students preform knowledge construction and challenge individual thoughts in order to come up with a joint solution that's takes everyone's point of view into perspective (Nastasi, 1999). Many researchers have concluded that collaborative learning, is a very beneficial learning method when it comes to challenging thoughts and concepts between students. Because each individual has a different thought process and ideas, each student brings a different concept that can be challenged and discussed among the group. Many researchers have previously studied the benefits of collaborative learning as well as the teacher's role in correctly facilitating and implementing it. Webb, highlights the importance of teachers actively pushing students to collaborate and challenge ideas. She states "In classrooms in which teachers pushed students to make explicit the steps in their mental processes (whether students' answers and strategies were correct or incorrect), collaborative groups engaged in frequent explaining and provided explanations that were correct and complete" (Webb, 2009, pg.18). Similarly, researchers such as Rijkje Dekker and Marianne Elshout-Mohr argue that collaboration in classrooms is especially important in terms of the type of work that is assigned. Assignments that require collaboration generally go more in depth and are considered more challenging than those given in individual assignments "Collaborative learning tasks are in general designed as complex, challenging and authentic problems. Such problems motivate students to attempt different strategies and co-construct and justify solutions" (Elshout-Mohr and Dekker, 2000, pg.40). Collaboration in language learning classrooms is beneficial and quite easy to implement (Elshout-Mohr and Dekker, 2000).
ContributorsAhmad, Nshwah Khalil (Author) / Wylie, Ruth (Thesis director) / Li, Na (Committee member) / School of Human Evolution and Social Change (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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De Plantis Aegypti is a medical botany text from 1592, written by Prospero Alpini in Latin. In this text, Alpini details a variety of plants native and grown in Egypt, how they are grown, how they are processed, what they look like, and what if any edible and medical uses

De Plantis Aegypti is a medical botany text from 1592, written by Prospero Alpini in Latin. In this text, Alpini details a variety of plants native and grown in Egypt, how they are grown, how they are processed, what they look like, and what if any edible and medical uses are documented. This project focused on transcribing and editing the Latin text, translating the Latin text into English, and comparing the medical claims to the modern scientific literature. This is the first translation of this text into English or any other language. Alpini also wrote two other books, which also have never been translated. The intended goal was to demonstrate that renaissance scholars understood medicine well, if not the mechanisms through which those medicines worked. After analyzing the modern scientific literature on the plants mentioned within the text, it was found that every medical use referenced in the text was either directly supported, indirectly supported, or there was no data from the literature. In other words, none of the medical uses were found to be disproved. On the other hand, quite a few of the plants actually had similar efficacies as modern pharmaceuticals. In addition to the notes on the modern science, there are also quite a few notes based on the grammar and the orthography of the text. This project is but a sampling of the plants mentioned De Plantis Aegypti, there are dozens more, which I plan on translating and doing a similar analysis on at a later date.
Created2016-05